The present invention relates to electronic battery testing and measuring. More specifically the present invention relates to a method and apparatus for measuring and checking parameters such as voltage, cold cranking amperage (CCA), state of charge (SOC) and state of health (SOH) of a standard battery.
Different methods were developed over the years in order to measure the power status and condition of lead acid batteries, such as those used in Vehicles, UPS systems, and in solar energy arrangements etc.
One such measuring method is taught in U.S. Pat. No. 5,598,098, wherein battery condition and measurement parameters are obtained through a correlation analysis. The method is based on battery conductance measurement.
Another prior art method (U.S. Pat. No. 6,441,585) uses measurements of impedance or admittance. Another, uses the measurement of OCV (U.S. Pat. No. 6,366,054). Still another prior art measurement method uses special battery loading during a limited period of time (U.S. Pat. No. 6,369,577).
In the aforementioned patents, the received measurement parameters are scaled with battery conditions by correlation analysis methods. Additionally, the tester system suggested in the aforementioned patents displays the battery's physical conditions to an operator. This prior art measurement technique is meant to be advantageous since it is executed with relatively low current. This is required for two reasons. First, it causes a minimum amount of battery discharge energy. Second, since the measurement process is long the battery can't be tested at high current conditions.
Essentially, it is desirable to check a battery's performance at high current (real time) conditions. The methods described above do not perform such test at high current conditions, but provide an estimation of high current condition results on the basis of extrapolating measurement results of tests conducted at low current conditions.
The disadvantage in using the aforementioned methods is the inaccurate results received for predicting the CCA, SOC and SOH. These inaccurate results stem from the fact that the battery performance test is executed at low current conditions over a relatively long period of time.
The aforementioned methods are also used (or-may also be used) for the purpose of predicting a battery's ability to start engines of different devices, such as of vehicles or for the purpose of measuring the voltage and current supply to a starter. The measurement results are processed and analyzed in order to determine a battery's ability to start an engine. The main drawback is that the results only reflect a successful ability to start the engine, without offering any solution for failed trials.
In most prior art methods it is not possible to estimate a battery's ability to start a specific type of vehicle's engine.
A different method for testing devices' batteries is based on checking the contact conditions between the tester clamps and the battery poles. Accurate measurements of the quality and condition of the contact between the tester clamp and battery poles are obtained by employing the Kelvin contacts (as described in patent NO. U.S. Pat. No. 5,592,092).
The Kelvin contact is based on checking the bridge balance between four clamp wires. This method is not easy to use or operate, and a more user-friendly method is in demand.
Therefore, there is a need for a battery measurement method and apparatus that provides more accurate results without damaging the battery.
Furthermore, there is a need for a method and apparatus that will predict not only the engine's ability to start, but also the ability to start at different temperature levels.